crumbs, where to start?
it will be difficult taking on 2 rescues at the same time.
if it was
me id be using a crate alot, 1 to help house training, and 2 to
give them security. forget about the romantic notion of them running free for the moment, treat them as den animals until they have a good secure routine and they feel safe. especially the blind one, as it must be all really scary for him, marking is normal.
my dogs sleep in the conservatory as a rule unless they are invited into the front room. the conservatory tiled is very easy cleaned so spraying/accidental pooping etc isnt a big deal. they are happy as its normal for them.
i personally wouldnt be putting your dogs straight into a furnished house. things like tables and couches are so tempting to pee on! dogs dont have to live inside the house, maybe a kennel would suit, it may even be better if it gives the blind one time to adjust to the changes in his life.
the best book iv ever read on house-training was written by monks who lived in a posh monastry (and bred dogs) and all puppies were literally tied to the monks (1:1) so they had no chance of running off to hide and pee.
this technique might suit you when you dogs are invited into your house - pop a lead on and tie it to your belt, so where you go - they go. youd also act as a guide for the blind dog and help build a relationship with him.
i think all the behaviour you have described is predictable and to be expected. keep a strict routine, use crates.
i wouldnt be putting a blind unsocialised dog loose amongst other strange dogs - it would be completely scary and alien to him. give him a den and increase his space very gradually. his mindset may be set firmly now if he hasnt been socialised at all. you can only do your best. but think from the dogs perspective, not human one.
put things in order of priority for them - food, water, bed, safety, health then exercise and stimulation. dont think about grassy meadows and freedom - that will come in time.
what im trying to say is - make life easier for yourself and dont feel they
need couches and the run of the house because they have had a tough life before- especially it makes you stressed by constantly cleaning up pee and poop.
not all dogs like eachother. my terrier and lhaso apso really dont like eachother and i dont expect that to change. we just have to manage them, or they would be at eachothers throats.
good luck and best wishes
what part of the country are you in?